It's not worth it. The value of C is in compatibility, availability of compilers, and familiarity.

As soon as you change anything in a breaking way, start requiring your own compiler/transpiler, or introduce new idioms, you end up losing the things that keep C alive.

Users of C either like it exactly the way it is, or have to use a specific C version due to a vendor dependency or compliance.

An upgraded C not approved by the standards body gives you yet another niche language that is not C, but is still burdened with its old flaws.